The common otter is classified as Near Threatened (NT) on the IUCN Red List (1). Listed under CITES Appendix I and III (4), Appendix II of the Bern Convention and Annex II of the EC Habitats Directive (5). Protected in the UK by Schedule 5 of the Wildlife and Countryside Act 1981 (as amended) (3).

The elusive common otter (Lutra lutra) has sleek brown fur, which is often paler on the underside, and a long lithe body with a thick tail and short legs (2). Adaptations for an aquatic lifestyle include webbed feet (2), the ability to close the small ears and the nose when under water, and very dense, short fur which traps a layer of air to insulate the animal. Many sensitive hairs ('vibrissae') frame the snout; these help the otter to locate prey (2).

The vocalisations of the common otter include a high-pitched whistle between a female and her cubs, twittering noises produced during play-fighting and cat-like noises when fighting (2).

Once widespread throughout the UK, the common otter is now largely restricted to Wales, south-west England, Scotland and Northern Ireland (4), is scarce in the east and south-east and absent from central England (5). It occurs throughout most of Eurasia, to the south of the tundra line, as well as in North Africa (2).

Found by clean rivers, lakes and along coasts. Otters living on the coast also require a source of fresh water with which to clean their fur (3) in order to retain its insulating properties (2).

Common otters feed mainly on fish, and the occasional water bird or frog may also be taken (3). Up to 15 percent of an individual's body weight in fish may be consumed daily (2). Common otters mark their large territories by depositing faeces ('spraints') in various prominent places (3).

Breeding can occur throughout the year; two or three cubs are usually born in a den known as a holt, and ten weeks later the cubs emerge above ground with their mother (3). Female common otters care for their offspring for about a year; it may take the cubs up to 18 months to learn to fish, and the female helps this learning process by releasing live fish for the cubs to re-catch (2).

Common otter fur was once highly prized, and for many years the species was hunted for this reason, for 'sport', and to protect fish stocks (2). Throughout most of Europe and Britain, common otter numbers declined drastically in the late 1950s and early 1960s. Habitat loss and pollution played a major part in the decline (3). Furthermore, many otherwise suitable rivers lack enough tall vegetation for otters to conceal their holts and to rest in (3).

The common otter has a low rate of population growth due to the extended period of maternal care, the small size of litters and the short average lifespan of about four years (2).

Some areas managed as 'otter havens' have been protected against human disturbance and had plenty of vegetation planted (2). Building artificial holts may also help the otter (5). In some cases, reintroductions of captive bred otters to parts of the former range have been successful (3), and natural recolonisation has occurred in some areas (2).

Under the EC Habitats Directive two areas have been proposed as SACs (Special Areas of Conservation) for the common otter. The species action plan produced as part of the UK Biodiversity Action Plan (UK BAP) aims to maintain and expand existing populations and ensure that by the year 2010, breeding populations have been restored to all catchments and coastal areas where post-1960 records exist (6).